<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
</head>
<body>
    <div style="height: 100px;border: 1px solid yellow;background-color: pink;">
        header
    </div>
    <div style="height: 300px;background-color: pink;">
        <div style="float: left;height: 100%;width: 20%;border: 1px solid yellow;">
            aside
        </div>
        <div style="float: left;;height: 100%;width: 79.5%;border: 1px solid yellow;">
            section
            <div style="float: right;height: 50%;width: 20%;background-color: aqua;">
                float
            </div>
        </div>
    </div>
    <div style="height: 100px;border: 1px solid yellow;background-color: pink;">
        footer
    </div>
</body>
</html>